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Graphical abstract Highlights • Na impregnation led to a migration of exchanged copper and CuO formation. • P impregnation led to Cu-P interactions. • Both Na and P poisons led to the decrease in ammonia adsorption capacity. • NOx conversion at 250 °C is mainly correlated with the NH 3 adsorption capacity. • NOx conversion at 500 °C is mostly directed by copper exchanged ratio. Abstract To highlight the deactivation mechanisms encountered by minerals impurities from biodiesel, the effects caused by Na, P or (Na + P) additions were studied over a model Cu-FER catalyst. Na, P or (Na + P) were added by wet-impregnation in water in a wide concentration range up to 2 wt-%. The catalytic behaviors were evaluated by NH 3 /NO oxidation and standard/fast NH 3 -SCR reactions. In addition, a combination of several characterization techniques (ICP–AES, N 2 adsorption/desorption, XRD, NH 3 -TPD, NO adsorption monitored by FTIR and H 2 -TPR) was applied to provide useful information regarding the deactivation mechanism caused by the minerals addition. Sodium and phosphorus interacted differently with the Cu-FER catalyst. Na addition induced a loss of Brønsted acid sites and a back-exchange of Cu2+ with Na+, with formation of external CuO species, thus favoring the oxidation of NO and NH 3. After phosphorus addition, the exchanged Cu2+ species remained moderately affected, but direct interactions with copper were evidenced which were primarily responsible for catalyst deactivation toward the oxidation reactions. After equimolar addition of phosphorus and sodium, both Na and P effects were observed. For the NH 3 -SCR process, the ammonia adsorption ability, which depends on both acidity and copper units, appeared the main key parameter driving the catalytic activity at low temperature (T ≤ 250 °C). Phosphorus appeared to be the major responsible for catalyst deactivation after (Na + P) co-poisoning. [ABSTRACT FROM AUTHOR]

Abstract: A methodology for the evaluation of diesel soot oxidation catalysts by high-throughput (HT) screening was developed. The optimal experimental conditions (soot amount, catalyst/soot ratio, type of contact, composition and flow rate of gas reactants) ensuring a reliable and reproducible detection of light-off temperatures in a 16 parallel channels reactor were set up. The temperature profile measured in the catalyst/soot bed under TPO conditions when the exothermic combustion of soot takes place was shown to provide an accurate measurement of the ignition. Its reproducibility and relevance were checked. The results obtained with a reference noble metal free catalyst (La0.8Cr0.8Li0.2O3 perovskite) agree very well with literature data. Qualitative mechanistic features could be derived from these experiments, stressing the likely limiting step of oxygen transfer from catalyst surface to soot particulates to ignite the soot combustion. Ceria material was shown to be more appropriate than perovskite one. From an HT screening of a large diverse library (over 100 mixed oxides catalysts) under optimized conditions, about 10 new formulations were found to perform better than selected noble metal free reference materials. [Copyright &y& Elsevier]

Abstract: The conversion of biomass-derived crude oil towards H2 production was investigated using continuous catalytic steam reforming and sequential cracking/reforming processes. The performances of Pt/Ce0.5Zr0.5O2 and Rh/Ce0.5Zr0.5O2 catalysts deposited on cordierite monoliths were comparatively studied. The Pt-based catalyst showed better catalytic activity than Rh for steam reforming in the whole range of steam-to-carbon molar ratios (S/C) studied, the amount of added water determining the H2 yield for both noble metals. The best H2 yield (70%, corresponding to ∼49mmol of H2/g of bio-oil) was obtained with the Pt catalyst at S/C ratio of 10 at 780°C, with CH4 concentrations below 1%. In the case of sequential cracking, the process alternated cracking steps, during which the bio-oil is converted into H2, CO, CO2, CH4 and carbon stored on the catalyst, with regeneration steps where the deposited coke was burnt under O2. Comparison with thermal bio-oil cracking showed that the catalyst plays a major role in enhancing the H2 productivity up to 18mmol of H2/g of bio-oil (∼50% of H2 in gaseous products stream) and lowering the CH4 formation. The steam reforming offers high yields towards H2 but is highly endothermic, whereas the sequential cracking, despite lower H2 yields, offers a better control of coke formation and catalyst stability, and due to lower energy input can theoretically run auto-thermally. [Copyright &y& Elsevier]

Abstract: Conversion of crude pyrolysis bio-oil for H2 production is investigated using a sequential process which alternates (i) cracking reaction steps, during which the bio-oil is converted to syngas and carbon stored on the catalyst and (ii) regeneration steps allowing to combust coke under an air flow. The performances of Pt and Rh catalysts supported on ceria-zirconia in powder form or deposited on cordierite monoliths are comparatively studied. From these data and calculated thermodynamic equilibrium, the co-existence of thermal and catalytic processes is demonstrated. A stable hydrogen productivity up to ca. 18mmol of H2 g−1 of bio-oil (∼50% H2 in the gas stream) with a minimized methane formation (ca. 6%) is obtained with the monolith configuration. Both Pt and Rh-based catalysts allow a good control of carbon formation, the coke being fully combusted during the regeneration step. Slow deactivation phenomena and selectivity changes along time on stream, mostly observed for platinum powder samples, are related to changes in catalyst structure and to the peculiar role of oxygen stored in the zirconia-ceria support. The heat balance evaluation of the sequential cracking/regeneration cycle shows that the process could be auto-thermal, i.e., minimizing the energy input, being competitive with conventional steam-reforming process under the same operating temperature. [Copyright &y& Elsevier]

Abstract: Recent results on catalytic wet air oxidation applied to a membrane contactor are presented that give new insight following a series of previous publications. Model and industrial effluents are treated in both single tube and multichannel catalytic systems. Characterisation of the catalytic material (solid analyses, electron microscopy, EDS and EPMA) is carried out, in order to determine the catalyst distribution. Catalytic results show performances heavily dependent on the nature of the effluent and the operating conditions, and to a lesser extent on the catalytic membrane characteristics. At 80°C, an industrial effluent is oxidised at a membrane surface related rate of 3.8mmol/s/m2. This result is achieved using a membrane containing about 0.1wt.% Pt. This allows a revised and improved technico-economical evaluation of the Watercatox process. [Copyright &y& Elsevier]

Abstract: A new and innovative method for oxidation of dissolved compounds in water – the “Watercatox” process – has been developed in order to reduce the chemical oxygen demand and the total organic carbon in industrial wastewaters. This process is the result of a European Fifth Framework Program project. It can operate at much lower temperatures and pressures than conventional wet air oxidation or incineration, and it offers much smaller volume requirements than biological treatment plants. The operating principle of the Watercatox process is the oxidation of the dissolved molecules using oxygen from air within a catalytic membrane reactor in an interfacial contactor configuration. The catalytic contactor membranes, as well as the operating conditions, have been up-scaled from lab-scale to pilot unit. The technological efficiency was demonstrated by the results obtained using the pilot test unit on different industrial effluents from several origins. [Copyright &y& Elsevier]

Abstract: This paper deals with the influence of catalytic membrane structure on the way the gas pressure affects the efficiency of a catalytic membrane reactor (CMR). The CMR is an interfacial contactor, used for wet air oxidation, formic acid solution and air being fed separately from both sides of the catalytic membrane. The gas overpressure can shift the gas–liquid interface into the membrane wall, closer to the catalytic zone, and therefore greatly increase the reaction rate. It has been confirmed that this was not an oxygen partial pressure effect. When compared to a conventional slurry reactor, the contactor CMR showed a reaction rate more than three times higher. [Copyright &y& Elsevier]

Catalytic Membrane Reactors combine a membrane that controls transfers and a catalyst that provides conversion. This paper focuses on the catalytic performance stability of interfacial contactor membranes in the wet air oxidation of formic acid. Stable catalytic membranes with high activity have been developed. [ABSTRACT FROM AUTHOR]

Abstract: Following the development of a high-throughput (HT) methodology for the evaluation of diesel soot oxidation catalysts in a 16 parallel channels reactor, a library of over 60 catalysts was tested under optimized conditions. The catalyst compositions were chosen to include solids which specific properties like oxygen storage capacity, oxygen mobility and ionic conductivity. The key parameters for high activity appear related to the presence of active and mobile surface oxygen species, and to an appropriate catalyst particle size in order to favour the number of contacts with the soot. In contrast, high oxygen storage capacity and bulk oxygen ion mobility do not appear as relevant properties for high catalytic activity. Nine new formulations were found to perform better than the reference catalyst “high surface area (HSA) ceria” (Rhodia). [Copyright &y& Elsevier]

Graphical abstract Highlights • Soot oxidation reactivity can be correlated with the structure and morphology. • Real soot has larger promotion on non-catalytic reactivity in NO 2 + O 2. • Soot catalytic oxidation in NO + O 2 has higher reactivity than that in NO 2 + O 2. • The reactivity under different contacts follows the order: tight > pressure > loose. Abstract The aim of the present work is to investigate and compare the non-catalytic and catalytic reactivities of real and model soot samples through temperature-programmed oxidation (TPO). Such reactivity was furthermore correlated with soot structural properties, determined by laser granulometry, XRD, Raman and HRTEM. Biodiesel soot samples were obtained through the combustion of different fuels in a real engine, whereas model soot samples were produced in a laminar burner. TPO evidenced that the soot generated with 100% Biodiesel (methyl ester) was more reactive than real soot generated with 7% Biodiesel (7% methyl ester). The model soot from the diesel surrogate (Aref) containing 7% oxygenate additive (C 11 H 22 O 2) exhibited higher reactivity than the model soot containing 30% additive, whereas a carbon black (Degussa Printex U) showed the poorest reactivity of this series. The presence of NO 2 promoted the non-catalytic oxidation of real soot. In the presence of the MnO x -CeO 2 catalyst, soot reactivity depended both on reactant gas composition and on soot-catalyst contact. [ABSTRACT FROM AUTHOR]

The effect of the sodium addition mode was investigated on model Cu/FER selective catalytic reduction (SCR) catalysts with two copper loadings (2.8 wt. % and 6.1 wt. %) in order to compare samples with or without over-exchanged copper. Na was added by wet-impregnation using two solvents: water or ethanol. Catalysts were evaluated in Standard and Fast-SCR conditions, as well as in NO and NH3 oxidation. They were characterized by H2-TPR, NO and NH3 adsorption monitored by FT-IR. As expected, whatever the copper loading, ammonia adsorption capacity was decreased by Na additions. Interestingly, characterizations also showed that Na impregnation in water favors the migration of the Cu-exchanged species, leading to the formation of CuO extra-framework compounds. Consequently, for both copper loadings, Na impregnation in water led to a stronger catalyst deactivation than impregnation in ethanol. Finally, the NOx conversion at low temperature (250 °C) appeared mainly affected by the loss in NH3 adsorption capacity whereas the deNOx deactivation at high temperature (500 °C) was rather governed by the decrease in the exchanged copper ratio, which also induced a partial inhibition of NO and NH3 oxidation behaviors. [ABSTRACT FROM AUTHOR]

The aim of this paper is to evaluate the effect of oxygenated compounds concentration on sooting propensities of surrogate Diesel and Biodiesel, and to investigate the oxidative reactivity of soot obtained by combustion of these surrogates using an atmospheric axis-symmetric co-flow diffusion flame burner. For this end, concentrations from 3 to 30% (in mole%) of methyl decanoate (MD) are added to a surrogate Diesel made up of a binary mixture of 70% of n -decane and 30% of α-methylnaphthalene (α-MN). The sooting propensities of these mixtures are here measured in terms of Yield Sooting Indices (YSIs) in methane diffusion flames doped with 35,000 ppm vapors of tested surrogate. Data of soot volume fraction were extracted using light extinction method (LEM). Additionally, soot generated from the combustion of the model Diesel and Biodiesel fuels was then collected, sampled and characterized using physico-chemical techniques. Addition of MD was found to reduce sooting tendencies. This decrease is more pronounced when the concentration of oxygenate additives increases. On the other side, the oxidative reactivity of soot generated from the diffusion flame burner was found to decrease by increasing Biodiesel percentage. Furthermore, soot generated from the combustion of surrogate Diesel and Biodiesel showed different behaviors. Biodiesel-derived soots were smaller and less reactive than Diesel-derived soots. These last displayed less ordered graphite-like structures and higher amorphous carbon concentration. [ABSTRACT FROM AUTHOR]

The impact of Biodiesel impurities (Na, K and P) on the non-catalytic and catalytic reactivity of Diesel soot was evaluated under model DPF (Diesel Particulate Filter) regeneration conditions. Temperature-programmed oxidation (TPO) measurements confirmed that Na and K depositing into soot or on the surface of the catalyst enhanced the oxidative reactivity of soot under both O 2 and NO x + O 2 and Na-doped samples showed better results. However, the presence of P inhibited the non-catalytic and catalytic reactivity. These findings can be mainly attributed to the changes in nanostructure and surface chemical properties of the doped samples, characterized by Raman, high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), H 2 temperature-programmed reduction (H 2 -TPR) and NO temperature-programmed oxidation (NO-TPO). The result of this characterization evidenced that the presence of Na and K increased structural defects of soot and reduction ability of the catalyst. Moreover, Na-/K-doped catalysts presented higher oxidizing ability of NO into NO 2 , whereas the opposite trend was observed for the P-containing catalysts. In addition, higher structural disorder of Na-doped soot and higher alkali metal content on the surface of Na-doped catalyst might lead to enhanced reactivity in comparison to K-doped soot and catalyst. Unlabelled Image • Impact of Biodiesel impurities on non-catalytic and catalytic reactivity of soot • Na and K have a positive effect on DPF regeneration. • Alkali metals increase structural defects of soot and reduction ability of catalyst. • P exhibits a promotion on soot ignition under NO x. [ABSTRACT FROM AUTHOR]